Electromechanical brake apparatus and system with planetary gear

ABSTRACT

An electromechanical brake apparatus includes a housing supporting an inboard brake pad and an outboard brake pad for selective frictional contact with a rotor interposed longitudinally therebetween. The housing includes a mechanism cavity located longitudinally between the inboard pad and a motor having a sun gear motor output shaft. An adjuster ramp assembly indirectly receives torque from the motor. A spindle is provided for selectively moving the inboard brake pad longitudinally. The spindle is operatively connected with the adjuster ramp assembly to indirectly receive torque from the motor therethrough. A leading ramp assembly is configured to transmit applied torque from the motor to the adjuster ramp assembly. The leading ramp assembly receives stepped-up torque from the motor via the sun gear motor output shaft and a plurality of planet gears located radially between the sun gear motor output shaft and a toothed inner lumen of the leading ramp assembly.

TECHNICAL FIELD

This disclosure relates to an apparatus, system, and method for use ofan electromechanical brake and, more particularly, to a method, system,and apparatus of an electromechanical brake including a planetary gear.

The present application relates to co-pending patent applicationsentitled “Electromechanical Brake Apparatus and System with AdjustmentFeatures” (application Ser. No. 16/835,438) and “Electromechanical BrakeApparatus and System with Gearless Input from motor” (application Ser.No. 16/835,399), which are filed concurrently herewith and incorporatedby reference for all purposes.

BACKGROUND

Vehicle brake systems typically have a service brake that has servicebrake apply modes and a parking brake system that has parking brakeapply modes. During a service brake apply hydraulic pressure is appliedto move a piston. In recent systems, during a parking brake apply, anelectric motor and drive mechanism moves the piston to create theparking brake apply by pressing one or more brake pads against a brakerotor. Once the parking brake apply is complete, the electric motor isturned off. Typically, several gear and/or belt stages and a rotary tolinear stage (e.g., lead screw) are located between the piston and themotor.

SUMMARY

In an aspect, an electromechanical brake apparatus is described. Ahousing supports an inboard brake pad and an oppositely facing outboardbrake pad for selective frictional contact with a rotor interposedlongitudinally therebetween. The housing includes a mechanism cavitylocated longitudinally between the inboard pad and a motor having a sungear motor output shaft. An adjuster ramp assembly indirectly receivestorque from the motor. A spindle is provided for selectively moving theinboard brake pad longitudinally. The spindle is operatively connectedwith the adjuster ramp assembly to indirectly receive torque from themotor therethrough. The spindle and adjuster ramp assembly are locatedsubstantially within the mechanism cavity. A leading ramp assembly isconfigured to transmit applied torque from the motor to the adjusterramp assembly. The leading ramp assembly receives stepped-up torque fromthe motor via the sun gear motor output shaft and a plurality of planetgears located radially between the sun gear motor output shaft and atoothed inner lumen of the leading ramp assembly. A predetermined amountand direction of torque is applied to each of the adjuster ramp assemblyand the leading ramp assembly to assist with a selected one of (1)service brake application and (2) service brake release functions. Theelectromechanical brake apparatus is operative, at different times, forboth functions.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding, reference may be made to the accompanyingdrawings, in which:

FIG. 1 is a schematic side view of an electromechanical brake apparatus;

FIG. 2 is an exploded partial view of components of theelectromechanical brake apparatus of FIG. 1;

FIG. 3 is a partial schematic front view of several components of theelectromechanical brake apparatus of FIG. 1;

FIGS. 4A-4E schematically depict components of the electromechanicalbrake apparatus of FIG. 1 in a sequence of example operating conditions;and

FIGS. 5-9 schematically depict the electromechanical brake apparatus ofFIG. 1 in a sequence of example operating conditions.

This application includes an appendix that forms an integral part ofthis application. Appendix A provides an example implementation.

DESCRIPTION OF ASPECTS OF THE DISCLOSURE

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of ordinary skillin the art to which the present disclosure pertains.

As used herein, the singular forms “a,” “an”, and “the” can include theplural forms as well, unless the context clearly indicates otherwise. Itwill be further understood that the terms “comprises” and/or“comprising,” as used herein, can specify the presence of statedfeatures, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features, steps,operations, elements, components, and/or groups thereof.

As used herein, the term “and/or” can include any and all combinationsof one or more of the associated listed items.

It will be understood that when an element is referred to as being “on,”“attached” to, “connected” to, “coupled” with, “contacting”, “adjacent”,etc., another element, it can be directly on, attached to, connected to,coupled with, contacting, or adjacent the other element, or interveningelements may also be present. In contrast, when an element is referredto as being, for example, “directly on,” “directly attached” to,“directly connected” to, “directly coupled” with, “directly contacting”,or “directly adjacent” another element, there are no interveningelements present. It will also be appreciated by those of ordinary skillin the art that references to a structure or feature that is disposed“directly adjacent” another feature may have portions that overlap orunderlie the adjacent feature, whereas a structure or feature that isdisposed “adjacent” another feature might not have portions that overlapor underlie the adjacent feature.

Spatially relative terms, such as “under,” “below,” “lower,” “over,”“upper”, “proximal”, “distal”, and the like, may be used herein for easeof description to describe one element or feature's relationship toanother element(s) or feature(s) as illustrated in the figures. It willbe understood that the spatially relative terms can encompass differentorientations of a device in use or operation, in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures.

As used herein, the phrase “at least one of X and Y” can be interpretedto include X, Y, or a combination of X and Y. For example, if an elementis described as having at least one of X and Y, the element may, at aparticular time, include X, Y, or a combination of X and Y, theselection of which could vary from time to time. In contrast, the phrase“at least one of X” can be interpreted to include one or more Xs.

It will be understood that, although the terms “first,” “second,” etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. Thus, a “first” element discussed below couldalso be termed a “second” element without departing from the teachingsof the present disclosure. The sequence of operations (or steps) is notlimited to the order presented in the claims or figures unlessspecifically indicated otherwise.

The invention comprises, consists of, or consists essentially of thefollowing features, in any combination.

FIG. 1 depicts an electromechanical brake apparatus 100 for use as aservice and/or parking brake, comprising a housing 102 directly orindirectly supporting an inboard brake pad 104 (e.g., via the use of abracket, not shown) and an oppositely facing outboard brake pad 106 forselective frictional contact with a rotor (shown schematically at 108)interposed longitudinally therebetween. An electromechanical brakeapparatus 100 generally is an all-electric caliper that performs serviceand/or parking brake events. The housing 102 includes a mechanism cavity110 located longitudinally between the inboard pad 104 and a motor 114,which could, for example, be a brushless direct current motor (“BLDC”)or axial flux motor.

Unlike known electromechanical brake apparatuses, the electromechanicalbrake apparatus 100 shown in FIG. 1 does not use a reducing gear unitinterposed mechanically between the brake apparatus and the motor 114 tostep up or alter the output torque from the motor 114 to reduce therotation speed and/or increase the torque provided to theelectromechanical brake apparatus through a suitable input. Instead, inthe present electromechanical brake apparatus 100, the motor 114connects directly to the electromechanical brake apparatus 100 via a sungear motor output shaft 118. The sun gear motor output shaft 118interacts with at least one planet gear 116 to provide torque (usedherein to indicate rotationally oriented motive power) having apredetermined magnitude, speed, and rotation direction to a leading ramp648 of a leading ramp assembly 140, serving as the ring gear of theplanetary gear system 112, for use by other components of theelectromechanical brake apparatus. Thus, the adjuster ramp assembly 120indirectly receives torque from the motor 114 through the leading rampassembly 140 and one or more ramp balls 142, as will be discussed below.(Though the present description references the transfer of “torque” forthe sake of description, it is contemplated that a non-angled force orload could also or instead be developed between components of theelectromechanical brake apparatus 100, and that the “torque” transferlanguage used herein could also encompass a situation where a non-torqueforce is at least partially involved.)

With reference to FIG. 3, the leading ramp assembly 140 receivesstepped-up torque from the motor 114 via the sun gear motor output shaft118 and at least one planet gear 116, such as the plurality of planetgears 116 shown, located radially between the sun gear motor outputshaft 118 and a toothed inner lumen of the leading ramp 648 of theleading ramp assembly 140. The term “radially” is used herein toindicate a direction which is perpendicular to the longitudinaldirection. The leading ramp 648 itself serves a torque-amplifyingfunction, as a component of the power transmission assembly, in a mannerthat was provided by separately provided gearboxes in prior art devices.

An adjuster ramp assembly 120 indirectly receives torque from the motor114, such as via the output shaft 118. The adjuster ramp assembly 120may include, for example, an adjuster ramp 222 and a clutch 224 whichcould, for example, assist with clutching or motion-arresting functionsin the apparatus 100. A threaded or unthreaded spindle 126, which couldbe, e.g., a rod may be provided for selectively moving the inboard brakepad 104 longitudinally. For example, on one side, the spindle 126 couldbe threadably connected with the adjuster ramp assembly 120 forlongitudinal motion therewith, and on the other side, via flange 432which may be substantially prevented from rotation by inboard pad 104;the spindle 126 may be likewise prevented from rotating under certainuse conditions. The spindle 126 may be operatively connected with theadjuster ramp assembly 120 to indirectly receive torque from the motor114 therethrough. (Though the present description references thetransfer of “torque” for the sake of description, it is contemplatedthat a non-angled force or load could also or instead be developedbetween components of the electromechanical brake apparatus 100, andthat the “torque” transfer language used herein could also encompass asituation where a non-torque force is at least partially involved.) Thespindle 126 and adjuster ramp assembly 120 are located substantiallywithin the mechanism cavity 110.

As shown in at least FIGS. 1 and 3, a boot 328 may be locatedlongitudinally between the inboard pad 104 and the adjuster rampassembly 120. The term “longitudinally” is used herein to indicate adirection parallel to arrow “L” in the Figures, or the left-rightdirection in the orientation of FIG. 1. The boot 328, when present,substantially prevents ingress of material into the mechanism cavitysuch as, for example, by sealing against an open end of the mechanismcavity 110 and preventing dirt, debris, and moisture from traveling froma location adjacent the inbound pad 104 and into the mechanism cavity110. In some use environments, the radial spacing between the ID(sealing on the spindle 126) is to reduce the volume of air between newand worn pads. If this volume is reduced to or below a predeterminedlevel, then vacuum generated inside the hermetically closed mechanismcavity 110 will also be desirably low.

As shown in FIGS. 1 and 2, a shield 430 may be interposed longitudinallybetween the boot 328 and the inboard pad 104. When present, the shield430 may be connected to the spindle 126, such as via flange 432, forlongitudinal travel therewith. The shield 430 facilitates egress ofmaterial from longitudinally between the boot 328 and the inboard pad104. The shield 430 may also serve as desired to stiffen the boot 328.The culmination of the boot 328 in the shield 430 may help prevent stoneentrapment between the flange 432 and other components of theelectromechanical brake apparatus 100, protect the boot 328 from stonedamage and puncture, and/or allow (muddy) water and debris to flow in adesirable “draining” direction for removal from the electromechanicalbrake apparatus 100 via gravity. Particularly when the shield 430 lacksdrain holes, the boot 328 may include a lip seal feature to interfacewith the shield 430 to prevent debris ingress.

FIG. 2 depicts the manner in which the boot 328, spindle 126, spacer534, spring 536, and adjuster ramp 222 are “stacked” together into apreliminarily assembled group 538, for later assembly into theelectromechanical brake apparatus 100, as will be discussed furtherbelow.

With reference back to FIG. 1, a leading ramp assembly 140 is configuredto transmit applied torque from the motor 114 to the adjuster rampassembly 120 via at least one ramp ball 142 longitudinally interposedbetween the actuated and adjuster ramp assemblies 140 and 120. Theleading ramp assembly 140 and at least one ramp ball 142 are locatedsubstantially within the mechanism cavity 110. The adjuster rampassembly 120 and the leading ramp assembly 140 are mechanically biasedlongitudinally toward each other with the ramp balls 142 interposedlongitudinally therebetween, under influence, for example, of at leastone of spring 536, thrust bearing 144 (which serves to facilitaterotation of the leading ramp assembly 140), and support 146. The thrustbearing 144 helps to facilitate rotation of the leading ramp assembly140 with respect to support 146 which, in some use environments, isconfigured to support the clamp load developed by the apparatus 100. Theleading ramp assembly 140 includes leading ramp 648.

Turning now to FIG. 2, an exploded view of the electromechanical brakeapparatus 100 is shown schematically. Through use of the ball ramp(comprising adjuster ramp 222, at least one ramp ball 142, and leadingramp 648), spindle 126, and other components of the electromechanicalbrake apparatus 100, a predetermined amount and direction of torque maybe applied from the motor 114 to each of the adjuster ramp assembly 120and the leading ramp assembly 140, via the planetary gear system 112.This predetermined amount and direction of torque may be used, to assistwith a selected one of (1) service brake application and (2) servicebrake release functions by the electromechanical brake apparatus 100.That is, the electromechanical brake apparatus 100 is operative, atdifferent times, to perform both of these listed functions. Thispredetermined amount and direction of torque may also be used to assistwith a selected one of (3) pad wear adjustment and (4) pad replacementfunctions. That is, the electromechanical brake apparatus 100 isoperative, at different times, to perform all four of these listedfunctions. It is contemplated, though, that only one of the performedfunctions will be performed at any chosen time, though they may each beperformed as often as desired, for any desired duration, and in anydesired sequence.

FIGS. 4A-4E schematically depict five different use conditions duringthe operative duty cycle of the ball ramp portion of theelectromechanical brake apparatus 100. In FIGS. 4A-4E, the“counterclockwise” direction (as viewed from the right to the left side,within the plane of the page of FIG. 1) is represented by the upwardfacing arrows, while the “clockwise” direction is represented by thedownward facing arrows. The left facing arrows represent a longitudinalexpansion of the adjuster ramp 222 and leading ramp 648 away from eachother under the influence of the ramp balls 142 and the known inwardfacing contours of those ramp discs.

In FIG. 4A, the ramps are in a “home” or neutral position, such as whenthe brakes are not applied. In FIG. 4B, the leading ramp assembly 140moves clockwise, to start the service brake application function with a“jump-out” (fast take-up of airgap). The clutch 224 on the adjuster rampassembly 120 prevents rotation of the adjuster ramp 222, to assist withmoving the ball ramp assembly to the position of FIG. 4B. In order tojump out, a predetermined amount of torque is applied, which may dependupon factors such as the compression of spring 536. So, in order to jumpout, the clutch 224 should be set to rotate above the amount of torquewhich is used to further compress the spring 536.

Depending on pad wear, clamp force may or may not be generated in theFIG. 4B position. In FIG. 4C, the leading ramp assembly 140 has movedeven further clockwise than in FIG. 4B, pushing the adjuster rampassembly 120 longitudinally toward the inboard pad 104 to apply thebrake. The sequence of FIGS. 4B-4C is reversed to at least partially(or, depending upon pad wear, fully) release the service brake function.The sequence of FIGS. 4A-4B is reversed to fully release the servicebrake function and to generate air gap to reduce brake drag. It shouldbe noted that, under high loads, forces in the electromechanical brakeapparatus 100 sufficient to backdrive the motor unit 112 may bedeveloped, but the ramp positioning and dynamics shown in FIG. 4D canhelp to “protect” or “reset” the air gap in the system. It will bedesirable to preserve an air gap throughout operation of theelectromechanical brake apparatus 100, in certain special events, toavoid development of an unwanted “air hammer” type percussion effect inthe apparatus 100, which could damage the components thereof.

In all phases of operation of the electromechanical brake apparatus 100,it is contemplated that torque from the motor 114 could be provided atany desired magnitude and directionality, and the planetary gear system112 could be controlled to transform the torque provided from the motor114 as needed into a motive torque having the magnitude anddirectionality appropriate for the desired operation of theelectromechanical brake apparatus 100. For example, the number anddesign of teeth for the sun gear motor output shaft 118, planet gears116, and/or ring gear (leading ramp 648) could be adjusted appropriatelyto achieve desired torque.

It is contemplated, for example, that the fixed gear (support 146) mayhave an important role in establishing a gear ratio as desired. Thefixed gear (support 146) may have a different number of teeth than doesthe leading ramp 648. By forcing the planet gears 116 to simultaneouslyroll in both of these sets of teeth, gear multiplication occurs. Thiseffect is known as a “Wolfrom planetary gear” arrangement. In thedepicted embodiment of the electromechanical brake apparatus 100, forexample, there are six planet gears 116. This means that the differencein number of teeth between fixed gear (support 146) and the number ofteeth of the leading ramp (gear) 548 is also equal to six. Whether oneof these two sun/ring gear structures has six more or six fewer teeththan the other, the effect will be a change in gear ratio and a changein direction of rotation of the leading ramp 648.

Repeated braking events will cause the brake pads 104 and 106 to wearaway. Thus, the rotation used to start clamp force generation in FIG. 4Cincreases over time. If the position of the ball ramp assembly 140 onthe spindle 126 is not adjusted for pad wear, the rotation needed togenerate a desired clamp force may increase from the position shown inFIG. 4C to one more similar to FIG. 4E, which will be undesirable inmost use environments. Pad wear adjustment (using a rotation scheme suchas that shown in FIG. 4D) may be performed as frequently as desired,optionally being controlled by some pad wear indicator or value. It isalso desirable, in some use environments, for the pad wear adjustment tobe performed automatically so as to be an invisible or transparentprocess for the vehicle operator.

With reference to FIG. 4D, the leading ramp assembly 140 is rotated inthe counterclockwise direction up to the end of the ramp tracks of boththe leading and adjuster ramp assemblies 140 and 120, and then evenfurther counterclockwise rotation causes the adjuster ramp assembly 120,the leading ramp assembly 140, and the ramp balls 142 to rotatecounterclockwise with respect to the spindle 126. Accordingly, thethreadable connection between the spindle 126 and the adjuster rampassembly 120 causes the spindle 126 to move longitudinally away from theadjuster ramp assembly 120 to push the inboard pad 104 longitudinallyaway from the mechanism cavity 110 and toward rotor 108, and thuscompensate for wearing away of the inboard and/or outboard pads 104 and106.

To replace worn pads, first the electromechanical brake apparatus 100should be moved (e.g., rotated) out engagement with the brake pads 104and 106. Next, a service tool (not shown) could be used to prevent theflange 432 from rotation. Then, and as shown in FIG. 4E, clockwiserotation of the leading ramp assembly 140 up to the end of the ramptracks occurs, and then even further clockwise rotation causes theleading ramp assembly 140, the adjuster ramp assembly 120, and the rampballs 142 to rotate clockwise together with respect to the spindle 126.Accordingly, the threadable connection between the spindle 126 and theadjuster ramp assembly 120 causes the spindle 126 to move longitudinallytoward the adjuster ramp assembly 120 to assist with replacement of theinboard and/or outboard brake pads 104 and 106.

FIGS. 4A-4E have been summarized above in a very simple, schematicdepiction and description of operation of the electromechanical brakeapparatus 100. FIGS. 5-9 will aid the corresponding description belowregarding the operation of the electromechanical brake apparatus 100 asa whole to perform the four braking operation functions outlinedpreviously, under influence of the adjuster and leading ramp assemblies120 and 140 and ramp balls 142.

FIGS. 5-9 each schematically depict a different phase of operation of asystem 950 including the electromechanical brake apparatus 100. Forconsistency of description, rotational motion within the plane of thepage will be described as seen by an observer looking from the righttoward the left side of each Figure, but one of ordinary skill in theart will understand that a “clockwise” or “counterclockwise” direction,as referenced herein, would be reversed or apparently linear, dependingupon the position of the observer.

The system 950 includes a controller 952. The controller 952 isconfigured to selectively control actuation direction and magnitude oftorque applied to the electromechanical brake apparatus 100 by the motor114, for example, by controlling one or more of the motor 114 and theplanetary gear system 112. A position sensor 954 may be associated withthe motor 114. The position sensor 954, when present, may provide motorposition information to the controller 952. The controller 952 maydetermine a pad wear value responsive to the motor position information,among other functions of the controller 952 and/or the position sensor954; the pad wear value determination will be discussed below. When apad wear value is determined, the controller 952 may control the motor114 to selectively adjust a longitudinal position of the spindle 126responsive to the pad wear value.

As shown in FIG. 5, the output shaft 118 from the motor 114 is rotatingin a clockwise direction, which drives the leading ramp assembly 140 inthe clockwise direction, as well, due to the mechanical connectiontherebetween. That is, the leading ramp assembly 140 can be consideredto be at least partially moving in a first rotary direction with respectto a central axis of the spindle 126. The adjuster ramp assembly 120,following the leading ramp assembly 140, will move substantiallylongitudinally leftward to assist with the service brake applicationfunction, in the orientation of FIG. 5, in the direction of applicationarrow “A” shown in this Figure. Here, the ball ramp will start in theposition of FIG. 4A, and move through the “jump-out” position of FIG. 4Band into the brake application direction of FIG. 4C, where the adjusterramp 222 and leading ramp 648 move longitudinally apart. Because theadjuster ramp assembly 120 is operatively connected to the inboard pad104, motion of the adjuster ramp 222 in application direction A willcause the front face of inboard pad 104 to move in that same direction,from an initial point denoted by line H in FIG. 5.

As an aside regarding the Wolfrom planetary gear type nature of thepresent arrangement, when the motor 114 is rotating in a clockwisedirection, the leading ramp assembly 140 may be driven either in (1) aclockwise direction as well when the leading ramp 648 is configured withmore teeth than is the support 146, or (2) a counterclockwise directionwhen the leading ramp 648 is configured with fewer teeth than is thesupport 146. Each configuration results in a different gear reduction.

Once a desired clamp force is developed (which could be determinedthrough the use of one or more force sensors, not shown, and/or throughmotor 114 current draw), torque provided by the motor 114 is controlledto “hold” the inboard and outboard brake pads 104 and 106 against therotor 108 interposed longitudinally therebetween at a desired clampforce. When clamp load or force is developed, increased load in thethreads between the spindle 126 in the adjuster ramp assembly 120 alsoprevents rotation of the adjuster ramp 222 and/or the spindle 126. Forexample, because threads have sliding friction while balls have rollingfriction, the ball ramp will rotate with less torque than a threadedinterface. Thus, the spindle 126 will not rotate with respect to theadjuster ramp 222. This facilitates movement of the ball ramps betweenthe positions shown in FIGS. 4B-4D. If flange 432 were not preventedfrom moving once some clamp load is developed, then further clamp forcewould not be developed.

It is contemplated that the controller 952, the position sensor 954, orany other component of the electromechanical brake apparatus 100 orsystem 950 could record or “tare” a “home” position of the motor 114 (orone or more components thereof), the output shaft 118, the leading rampassembly 140 (or one or more components thereof), the inboard brake pad104, or any other component of the electromechanical brake apparatus 100before the brake application commences or at any desired other timeduring application of the brake, in order to provide a baseline value toaid with tracking pad wear. For example, the controller 952 could“memorize” the amount of rotation of the output shaft 118 needed toachieve a desired clamp force when the inboard and/or outboard brakepads 104 and 106 are relatively new, and then later compare that to aneeded rotation to “take up” the air gap between the inboard pad 104 andthe rotor 108 once the inboard pad 104 has worn down through repeatedapplications, to determine a pad wear value.

Turning now to FIG. 6, to release clamp force, the output shaft 118 fromthe motor 114 is rotating in a counterclockwise direction, which maydrive the leading ramp assembly 140 in the counterclockwise direction,as well, due to the mechanical connection therebetween. (This directioncould instead be counterclockwise, as previously mentioned, dependingupon the relative tooth counts of the leading ramp 648 and the support146, but will be presumed here to be clockwise, for the sake ofdescription.) That is, the leading ramp assembly 140 can be consideredto be at least partially moving in a second rotary direction (which iscounterclockwise, as shown herein) with respect to a central axis of thespindle 126, opposite the first rotary direction (which is clockwise, inthis example schematic depiction). The adjuster ramp assembly 120,following the leading ramp assembly 140, will move substantiallylongitudinally rightward to assist with the service brake releasefunction, in the orientation of FIG. 6, in the direction of retractionarrow “R” shown in this Figure. Here, the ball ramp will start aposition similar to that shown in FIG. 4C, and move through the“jump-out” position of FIG. 4B and into the home position of FIG. 4A,where the adjuster ramp 222 and leading ramp 648 move longitudinallytoward one another along that sequence. Because the adjuster rampassembly 120 is operatively connected to the inboard pad 104, motion ofthe adjuster ramp 222 in retraction direction R will cause the frontface of inboard pad 104 to move in that same direction, from a clampposition denoted by line C in FIG. 6 toward the initial position, H.

Once the clamp force is released as desired (which could be determinedthrough the use of one or more force sensors, not shown, and/or motor114 draw), the controller 952 will command motor 114 to return to homeposition as shown in FIG. 8A. When such home position is achieved,electrical power to the motor 114 is turned OFF. The inboard andoutboard brake pads 104 and 106 are then held in a “home” position untilthe next brake application is to be performed. Continued retraction ofthe adjuster ramp assembly 120 is facilitated through use of the spring536 to provide sufficient force to help urge the adjuster ramp assembly120 toward the “home” position.

As previously mentioned, the controller 952 or any other portion of thesystem 950 could have recorded a “tare” or “home” position of the motor114, planetary gear system 112, output shaft 118, or any other portionof the electromechanical brake apparatus 100 to record a baseline valuefor pad wear. The controller 952 or any other portion of the system 950could record and determine the adjusted value for pad wear at apredetermined time interval or apparatus event, such as upon everyservice/parking brake event application. If the difference between theadjusted pad wear value and the baseline pad wear value reaches apredetermined amount, the controller 952 or any other portion of thesystem 950 can alert an operator that the pad needs to be adjusted, butin most use environments will simply carry out the pad adjustment at apredetermined time during the use cycle of the electromechanical brakeapparatus 100 (for example, when the electromechanical brake apparatus100 is in the home position or otherwise when the adjustment will notinterfere with normal brake use—such as, but not limited to, when thevehicle is parked, transmission selector is moved to P or N, and/or thekey ignition is turned to OFF). One example of a physical characteristicof the system 950 which can provide an indication of the amount of padwear that has occurred is how much rotational motion of the output shaft118 is needed to develop a predetermined amount of clamp force. One ofordinary skill in the art will be readily able to provide one or moreadditional or alternative schemes for determining when an actionableamount of pad wear has occurred.

One example pad wear adjustment scheme is shown in the sequence of FIGS.7-8. In these Figures, the face of the inboard pad 104 has worn suchthat it no longer is located at line H in the home position, but is atline “H-W”. For the sake of description, it will be presumed that thedistance between line H and line H-W connotates sufficient pad wear totrigger a manual and/or automated pad wear adjustment, which could becarried out at any desired timing (e.g., the earliest opportunity underthe aforementioned example conditions) using the following procedure. InFIG. 7, the output shaft 118 from the motor 114 is rotating in acounterclockwise direction, which drives the leading ramp assembly 140in the counterclockwise direction, as well, due to the mechanicalconnection therebetween. That is, the leading ramp assembly 140 can beconsidered to be at least partially moving in a second rotary direction(which is counterclockwise, as shown herein) with respect to a centralaxis of the spindle 126, opposite the first rotary direction (which isclockwise, in this example schematic depiction). The adjuster rampassembly 120, following the leading ramp assembly 140, will movesubstantially longitudinally rightward as if it were assisting with theservice brake application function. However, here the ball ramp willstart in the position of FIG. 4A, and move to the pad adjustment end oframp position of FIG. 4D. The stroke between positions in FIGS. 4A and4D may be, for example, about 0.3 mm.

Further counterclockwise (as shown here) rotation of the leading rampassembly 140 in the second rotary direction (counterclockwise, asreferenced herein) from the position shown in FIG. 4D will cause theadjuster ramp assembly 120, the leading ramp assembly 140, and the rampballs 142 to rotate together in a unitary fashion in the second rotarydirection (e.g., clockwise, as shown here).

As a result, the adjuster ramp 222 rotates with respect to the spindle126. Since the spindle 126 cannot rotate due to its interlock with theinboard pad 104, the spindle will move in direction A, as shown in FIG.12, until the inboard pad 104 contacts the rotor 108, i.e. air gap iseliminated. This contact is detected by controller 952 and/or system 950through an increase in load by the force sensor (not shown) and/or anincrease in current draw by the motor 114. This will result in theinboard pad 104 being pushed longitudinally away from the adjuster ramp222, to compensate for the pad wear, and, upon return of the leadingramp assembly to “home” position as shown in FIG. 4A. thus urging theinboard pad 104 into the position shown in FIG. 8, with the front faceat line H, the air gap is reset to a desired air gap, for example about0.3 mm.

In other words, the leading ramp assembly 140 at least partially movesin the second rotary direction with respect to the spindle 126, oppositethe first rotary direction. The adjuster ramp assembly 120 then also atleast partially moves in the second rotary direction relative to thespindle 126, responsive to a predetermined amount of rotation by theleading ramp assembly 140, to assist with the pad wear adjustmentfunction. The spindle 126 is threadably connected with the adjuster rampassembly 120, such that the spindle moves longitudinally due to thethreadable connection, responsive to movement of the adjuster rampassembly 120 in the second rotary direction. When the ball ramp returnsto the home position of FIG. 4A, there will be an air gap (e.g., ofabout 0.3 mm in some use environments) generated immediately after padwear adjustment.

Once the inboard pad 104 is advanced further in the applicationdirection A to contact the rotor 108, some clamp force is developed. Thecontroller 952 turns off the motor 114 as a predetermined amount ofclamp force is reached. Since the electromechanical brake apparatus 100is not locked in position during the pad wear adjustment sequence, thecombination of clamp force, force from biasing spring 536, and any othersuitably applied force will back drive the mechanism of theelectromechanical brake apparatus 100 toward the home position, as shownin FIG. 8. It should be noted that the leading ramp assembly 140 rotatesclockwise, and both the adjuster ramp assembly 120 in the spindle 126move longitudinally in the retraction direction R during such aconclusion of a wear adjustment operation.

Finally, FIG. 9 schematically depicts a situation in which theelectromechanical brake apparatus 100 is undergoing a pad replacementoperation. In this Figure, the electromechanical brake apparatus 100 isrotated out of the way so that the flange 432 is no longer engaged bythe inboard brake pad 104. A service tool may be located between theflange 432 and the housing 102 fingers, which prevents rotation of theflange 432 throughout the pad replacement operation. Here, the leadingramp assembly 140 at least partially moves in the first rotary direction(clockwise, in the orientation of the Figures) with respect to thespindle 126, to an extent that the ramp balls 142 reach the furthestextent of their travel that direction and begin to force the adjusterramp assembly 120 to at least partially move in the first rotarydirection, as well, responsive to that predetermined amount of rotationby the leading ramp assembly 140. This action, shown schematically inFIG. 4E, may assist with a pad replacement function by “screwing” thespindle 126 inward toward motor unit 112 (toward the right side of thepage, in FIG. 9) until the unthreaded portion of the spindle 126 stopsagainst adjuster ramp 222. The boot 328 may be sufficiently flexible toat least partially extend or evert, as shown in FIG. 9, during the padreplacement operation to maintain sealing of the mechanism cavity 110 orfor any other reason. At this time, the motor unit 112 rotates the inputshaft 118 in the counterclockwise direction to bring the ball rampassembly into the position shown in FIG. 4A, and then electrical powerto the motor 114 is turned OFF. The worn pads may be replaced with newpads on the bracket (not shown), and the electromechanical brakeapparatus 100 is rotated back into place with attention to aligning thegroove on the flange 432 with the tabs on the inboard pad 104 to preventrotation of the flange 432. At this point, the pad replacement iscompleted. A pad wear adjustment operation may be performed to reset theposition of the spindle 126 with respect to the new, unworn brake padprior to normal brake operation. One of ordinary skill in the art willbe able to provide any desired control and/or mechanical arrangement tofacilitate such replacement, for a particular electromechanical brakeapparatus 100.

While aspects of this disclosure have been particularly shown anddescribed with reference to the example aspects above, it will beunderstood by those of ordinary skill in the art that various additionalaspects may be contemplated. For example, the specific methods describedabove for using the apparatus are merely illustrative; one of ordinaryskill in the art could readily determine any number of tools, sequencesof steps, or other means/options for placing the above-describedapparatus, or components thereof, into positions substantively similarto those shown and described herein. In an effort to maintain clarity inthe Figures, certain ones of duplicative components shown have not beenspecifically numbered, but one of ordinary skill in the art willrealize, based upon the components that were numbered, the elementnumbers which should be associated with the unnumbered components; nodifferentiation between similar components is intended or implied solelyby the presence or absence of an element number in the Figures. Any ofthe described structures and components could be integrally formed as asingle unitary or monolithic piece or made up of separatesub-components, with either of these formations involving any suitablestock or bespoke components and/or any suitable material or combinationsof materials. Any of the described structures and components could bedisposable or reusable as desired for a particular use environment. Anycomponent could be provided with a user-perceptible marking to indicatea material, configuration, at least one dimension, or the likepertaining to that component, the user-perceptible marking potentiallyaiding a user in selecting one component from an array of similarcomponents for a particular use environment. A “predetermined” statusmay be determined at any time before the structures being manipulatedactually reach that status, the “predetermination” being made as late asimmediately before the structure achieves the predetermined status. Theterm “substantially” is used herein to indicate a quality that islargely, but not necessarily wholly, that which is specified—a“substantial” quality admits of the potential for some relatively minorinclusion of a non-quality item. Though certain components describedherein are shown as having specific geometric shapes, all structures ofthis disclosure may have any suitable shapes, sizes, configurations,relative relationships, cross-sectional areas, or any other physicalcharacteristics as desirable for a particular application. Anystructures or features described with reference to one aspect orconfiguration could be provided, singly or in combination with otherstructures or features, to any other aspect or configuration, as itwould be impractical to describe each of the aspects and configurationsdiscussed herein as having all of the options discussed with respect toall of the other aspects and configurations. A device or methodincorporating any of these features should be understood to fall underthe scope of this disclosure as determined based upon the claims belowand any equivalents thereof.

Other aspects, objects, and advantages can be obtained from a study ofthe drawings, the disclosure, and the appended claims.

We claim:
 1. An electromechanical brake apparatus, comprising: a housingsupporting an inboard brake pad and an oppositely facing outboard brakepad for selective frictional contact with a rotor interposedlongitudinally therebetween, the housing including a mechanism cavitylocated longitudinally between the inboard pad and a motor having a sungear motor output shaft; an adjuster ramp assembly indirectly receivingtorque from the motor; a spindle for selectively moving the inboardbrake pad longitudinally, the spindle being operatively connected withthe adjuster ramp assembly to indirectly receive torque from the motortherethrough, the spindle and adjuster ramp assembly being locatedsubstantially within the mechanism cavity; and a leading ramp assemblyconfigured to transmit applied torque from the motor to the adjusterramp assembly, and the leading ramp assembly receiving stepped-up torquefrom the motor via the sun gear motor output shaft and a plurality ofplanet gears located radially between the sun gear motor output shaftand a toothed inner lumen of the leading ramp assembly; wherein apredetermined amount and direction of torque is applied to each of theadjuster ramp assembly and the leading ramp assembly to assist with aselected one of (1) service brake application and (2) service brakerelease functions, the electromechanical brake apparatus beingoperative, at different times, for both functions.
 2. Theelectromechanical brake apparatus of claim 1, wherein the spindle isthreadably connected with the adjuster ramp assembly.
 3. Theelectromechanical brake apparatus of claim 1, wherein the leading rampassembly is configured to transmit applied torque from the motor to theadjuster ramp assembly via at least one ramp ball longitudinallyinterposed therebetween, the leading ramp assembly and at least one rampball being located substantially within the mechanism cavity.
 4. Theelectromechanical brake apparatus of claim 1, including a boot locatedlongitudinally between the inboard pad and the adjuster ramp assembly,the boot substantially preventing ingress of material into the mechanismcavity.
 5. The electromechanical brake apparatus of claim 4, including ashield interposed longitudinally between the boot and the inboard pad,the shield being connected to the spindle for longitudinal traveltherewith and the shield facilitating egress of material from betweenthe boot and the inboard pad.
 6. The electromechanical brake apparatusof claim 3, wherein the adjuster ramp assembly and the leading rampassembly are mechanically biased longitudinally toward each other withthe ramp balls interposed longitudinally therebetween.
 7. Theelectromechanical brake apparatus of claim 1, wherein the leading rampassembly at least partially moves in a first rotary direction withrespect to the spindle and the adjuster ramp assembly movessubstantially longitudinally to assist with the service brakeapplication function.
 8. The electromechanical brake apparatus of claim7, wherein the leading ramp assembly at least partially moves in asecond rotary direction with respect to the rod, opposite the firstrotary direction, and the adjuster ramp assembly moves substantiallylongitudinally to assist with the service brake release function.
 9. Theelectromechanical brake apparatus of claim 1, wherein a predeterminedamount and direction of torque is applied to each of the adjuster rampassembly and the leading ramp assembly to assist with a selected one of(1) service brake application, (2) service brake release, (3) pad wearadjustment, and (4) pad replacement functions, the electromechanicalbrake apparatus being operative, at different times, for all fourfunctions.
 10. The electromechanical brake apparatus of claim 9, whereinthe leading ramp assembly at least partially moves in a first rotarydirection with respect to the spindle and the adjuster ramp assemblymoves substantially longitudinally to assist with the service brakeapplication function, and wherein the leading ramp assembly at leastpartially moves in a second rotary direction with respect to the rod,opposite the first rotary direction, and the adjuster ramp assembly atleast partially moves in the second rotary direction relative to therod, responsive to a predetermined amount of rotation by the leadingramp assembly, to assist with the pad wear adjustment function.
 11. Theelectromechanical brake apparatus of claim 10, wherein the spindle isthreadably connected with the adjuster ramp assembly and wherein thespindle moves longitudinally due to the threadable connection,responsive to movement of the adjuster ramp assembly in the secondrotary direction.
 12. The electromechanical brake apparatus of claim 9,wherein the leading ramp assembly at least partially moves in a firstrotary direction with respect to the spindle and the adjuster rampassembly at least partially moves in the first rotary direction,responsive to a predetermined amount of rotation by the leading rampassembly, to assist with the pad replacement function.
 13. A systemincluding the electromechanical brake apparatus of claim 1, the systemcomprising a controller, the controller being configured to selectivelycontrol actuation direction and magnitude of torque applied to theelectromechanical brake apparatus by the motor.
 14. The system of claim13, including a position sensor associated with the motor, the positionsensor providing motor position information to the controller, thecontroller determining a pad wear value responsive to the motor positioninformation, and the controller controlling the motor to selectivelyadjust a longitudinal position of the spindle responsive to the pad wearvalue.